Telephony.



M. L. JOHNSON.

TELEPHONY.

(APPLICATION FILED MAY 22, 1911.

Patented Mar; 18, 1913.

2 SHEETS-SHEET l.

2 SHEBTSSHEET 2.

Patented Mar. 18,1913.

TELEPHONY.

M. L. JOHNSON.

AP PLIOATION FILED MAY 22, 1911.

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Townhouse.

Specification. oi itettersratent. Y Patented liter, 18, int-3.

Application filed "MeyZQ, 1911, Serial No. scarce.

accompanying drawings, forming a part oi this specification.

My invention relates to that class of telephone exchange systems in which telephone lines are automatically-extended at an exchange, and while I have embodied. my in vention in an automatic telephone exchange system-wherein calling telephone linesare automatically connected with celled telephone lines, yet 1 do not limit myself to a system in which connection between calling and called subscribers'is eflected entirely by automatic operations at the exchange.

My invention has for its object the provision of improved means whereby a calling party at one of several stations upon a line,

. commonly known as party line stations, may

appropriate his line to the exclusion of other stations upon the same line whereby such calling party'may set the selecting meoha- .nism at the exchange into operation without having the operation of such selecting mechanism interfere with other parties atthe remaining stationsupon the same. party line.

in my application Serial No. 628,777, filed May 22, 1911, l have described a system for accomplishing the results above generally stated. In the equipment illustrated in said co-pending application I have shown a porized magnet at each of the party line ions which is off very high resistance. se magnets are included in bridge of the line and the circuit interrupting h' at each party 'line station is also included in bridge of the party line, for the purpose of operating the selecting mecha: nism at the exchange, the electro-magnets enabling acalling-party to hold his own party line to the exclusion of other party line stations upon theosame line.

in the systcm' formi'ng the subject matter of the present application I govern the operation of the selecting mechanism over a;

circuit whichis distinct from or supplied in addition to the party telephone line circuit whereby I am enabled. to simplify the con.

struction of the magnets and may also he able to reducetheir resistance, owing to the factthat the circuit for the magnets and the circuit for governing the operation of the selecting mechanism are distinct.

I. will explain my invention more fully by reference to the accompanying drawings showing an embodiment thereof in the form or an automatic telephone. exchange system, to which the invention is not to be limited, and in which drawings- Figure 1 shows a party telephone line with four stationsconnected therewith, and Fig. 2 shows the exchange end ofsaid party telephone line and automatically operated selecting mechanism for eilecting extension of the party telephone line.

The telephone line extends from the exchange to two limbs 1, 2 and, in the em bodimentof the invention illustrated, is normally connected .at-its side 2 with the negative pole of the grounded battery 3.

I have shown four party line stations A B C vl) though I .do not limit myself to the number of stations that are connected with the party line. As the invention is illustrated, the equipments at the four stations are identical except, if desired, the signal receivers at the different stations may be of harmonic type to respond to wa e form current of differentperiodicities to be selectively impressed upon the line at the exchange. The signal receivers may be alike, if desired, in which event code signals should be employed. Similar ports at the different stations will be given similar characters of reference, one station being specifically described. In the system illus trated, being an automatic telephone exchange system, I have illustrated a well the, return of the spring actuated mechanism to normal. The circuit which is interrupted at G is establish-ed for interrupt-ion by a switch 6 that is closed after the switch (F included in the telephone bridge is opened, the latter switch excluding the tele 5 phone outfits 10 and 1-1 from circuit so that the circuit for governing the operation of the selecting mechanism at the exchange is established independently of the telephone outfit, though I do not limit myself to this characteristic. The governing circuit men tioned has its switch 6 closed during the time the dial mechanism operates to open and close the switch 6. The governing circuit thus established at (5 during the circuit opening and closing operation of the dial may be-traced from the grounded contact of the switch 6 the companion to such contact, the contacts of the switch 6, the contacts 7 and 8 ofa master switch, the side 2 of the telephone line, the operating magnet 36 to the grounded battery, the side 1 of the telephone line, thus being excluded from the governing circuit. The telephone switch hook 9, when supporting the receiver 1t), operates to depress the element 8 of the master switch, and there open the circuit through switch 6, through the intermediation of the depressing finger 11 and the right hand end portion of the lever 12 then de- 30 pressed by the finger 11', this right hand end portion of the lever 12 being mechanically connected with the switching element 8 by means of a strut 13. The switch hook when depressed causes pawl 11 to hold the dial.

There is a low resistance bridge conductor at each telephone station that includes the telephone transmitter 14 having one terminal telephonicall-y connected with the limb 1 of the telephone line, the receiver 10 in serial relation withthe transmitter 1 1, the

dial switch 6, and the contacts 7 and 8. The

normally open connection which has just been traced between the sides of the telephone line is'in parallel relation with another bridge conductor which is desirably of high resistance and is preferably also open at the contacts 15, 16. This second bridge conductor includes a magnet 17 which is preferably non-polarized, and the entire resistance of this second bridge conductor is preferably located in the magnet which may belwound tor example, to one thousand ohmsresistancefi The armature of the magnet 17 is preferably held in predetermined normal position by means of a spring 18 that normally locks the nose or angular extension 19 of the armature beneath the'nose' or angu ar extension 20 of the intermediately pivoted lever 1-2. A spring 21 normally presses'the nose 29 against the nose 19. The contact element 16 is mechanically connected with the finger 11 so that said contact 16 "is permitted to engage the contact 15 when the associated tele;

phone receiver 10 at a calling station iing the magnet 17 is closed whereupon current from the battery 3 is permitted initial flow over the line sides to enable the 19 from engagement with the nose 20 of the lever 12 against the force of the spring 18 whereupon the spring 21 is permitted to swing the lever 12 in a counter clockwise direction, the finger 11 having previously been raised owing to the removal of the telephone from its switch hook. The contacts 7 and 8 of the master switch are thereupon engaged, whereafter the previously traced circuit for governing the selecting mechanism isestablished at (3 by the operation of the calling partys dial and has its continuity intermittently broken at 6 in a manner pose of operating the selecting mechanism at the exchange to extend the telephone line in a manner well known. During the im' pulse sending operation the side 1 of the telephone line is excluded from circuit as a consequence of the operation of the armature switch 39 and is attracted as a conseouence of the establishment of circuit through the magnet 36 and they sluggishly acting relay 40, this latter relay establishing circuit through sluggishly acting magnet 41 that governs the armatur switch 39, all as may readily be traced from the diagram, Fig. 2, the circuit for the magnet'40 being established through the armature switch of magnet 36 and the alternate contact ofsuch armature switch while the circuitfor magnet 41 is closed at the normal contact ofthe armature switch of relay '36. thiscontact being included in circuit with sufiicient duration within the period of impulse sending to maintain the sluggishly acting magnet 11 energized, the circuit for the magnet 41 including the alternate contact of the lowermost armature switch of the sluggishly acting magnet 40. As a consequence of this the magnet 17 at. a station late in seeking the line cannot be energized and therefore the telephone at this station cannot be included in circuit. The telephone at the station first taking the line, however, is included in circuit across the sides of the telephone line since at that time the operating magnet 36 has not been energized owing to the fact that the calling party does not operate his dial until after he removes his telephone from its switch hook. I also provide a 'pawl 11 that is normally held by the magnet to lock the dial so that the party at an intruding station'cannot operate his dial whereby the line is further guarded, supplementing the guard effected at 7 and 8. In this way I have provided a simple circuit arrangement for enabling a calling party line subscriber magnet 17 to operate and draw its armature which is well understood and for the purto appropriate his line to the exclusion of all other stations upon the same line.

It a party line subscriber is a called party such party may appropriate his line by simply removing his telephone from its switch hook whereupon a circuit-isestab iishcd through his magnet 17 that, maybe.

traced from the battery 3 through the upper winding through what is technically termed the back bridge relay 42 of the connector switch, the upper armature switch of the private relay 43, the armature switch 44 of the ringing relay 45, the connector wiper 46, the upper bank contact in engagement there with, the alternate contact of the armature switch 47, the line side 2, the contact 8 and the contact immediately beneath the same, the contacts 15 and 16 at the called station, the magnet 17 at the called station, the line side 1, the lowermost armature switch 48 of the line switch, the alternate contact of such armature switch, the lower bank contact and the wiper 49 engagingthe same, the

armature switch 50 of the ringing relay 4:5

paratus at this station so that 'sufficient current is diverted from the magnet 17 at another station seeking the line to prevent this other malgnetironi" operating whereby the dial mechanism at the intruding station is maintained locked and the master switch 7 8 is maintained open whereby the intruding party can neither operate his dial nor include his telephone" in circuit relation with the line.

While I have herein shown and particularly described the preferred embodiment of the invention I do not wish to be limited to the precise details of construction shown as changes may readily be made without departing from the spirit of the invention, nor

do Iwish to be limited to a telephone ex change system that is purely automatic its operation at the exchange.

Having thus described my invention, I claim as new and desire to secure by Letters Patent the following:

1. A telephone exchange system including a line connecting a plurality of telephone stations with an exchange; selecting mechanism at the exchange for extending the line thereat; a circuit supplied in addition to the line circuit for governing the operation of the selecting mechanism switching mechacircuit;- electrosmagnetic mechanism at ti nism at the telephone stations for operating 'the selecting mechanism over its governing circuit; electromagnetic mechanism at the stations in bridge of the telephone line serving when denergized to prevent-the operation of the switching'mechanism .at the telephone stations and when energized to permit the ope 'ation of said switching mechanism, there being present switching devices at the telephone stations for estal lishing circuit through the electro-magnetic mechanism thereat; and means governed at a telephone station for rendering ineffective the circuit of the clectro-magnetic mechanism at a companion telephone station.

- 2. A telephone exchange system including a line connecting a plurality of telephone stations with an exchange; selecting mechanism at the exchange for extending the line thereat; a circuit supplied in addition to the line circuit for governing the operation of the selecting mechanism switching mechanism at the telephone stations for operating the selecting mechanism over its governing stations in bridge-of the telephone line servingwvhen detinergized to prevent the operation of the switching mechanism at, the

telephone stations and whenenergized to permit the operation of said switching mechanism, there being present switching devices at the telephone stations for estab-- lishing circuit through the electro-magnet-ic mechanism thereat; and means operated the selecting mechanism when actuated in response to the switching mechanism "at a calling station on sa d line for rendering ineffective the circuit of the electro-magnetic mechanism at a companion telephone station 3,. A. telephone exchange system includii a line connecting a plurality of telephoiu stations with an exchange; selecting mechanism at the exchange for extending the l ne thercat; a circuit supplied inaddition to the line. circuit for governing the operation of the selecting mechanism; switching mecha' nism atthe telephone stations for operating the selecting mechanism over its governing circuit; electro-magnetic mechanism at the stations in bridge of the telephone line serving when denergized to prevent the inclusion of the telephones thereat in circuit with the line and when energized to permit the inclusion of the telephones thereat in circuit with the line, there being present switching devices at the telephone stations for establishing circuit through the electromagnetic mechanism thereat; and means governed at a telephone station for rendering ineffective the circuit for ele'ctro-mag netic mechanism at a companion telephone station. 1 p

4. A telephone exchange system including a line connecting a plurality ot' telephone stations with an exchange; selecting mecha nism at the exchange for extending the line thereat; a circuit supplied in addition to the line circuit for governing the operation of the selecting mechanism over its governing circuit; electromagnetic mechanism at the stations in bridge of the telephone line serving when deenergized to prevent the inclusion oi the telephones thereat in circuit with the line andwhcn deenergized to permit the inclusion ot the telephones thereat in circuit with the line, there being present switching devices at the telephone stations for est-abtishing circuit through the electronagnetic lmechanisnr thereat; and means operated by "the selecting mechanism when actuated in response to the switching mechanism at a calling station on said line for rendering ineffective the circuit of the electro-magnetic mechanism at a companion telephone station.

5. A telephone exchange system including a line connecting a plurality of telephone stations with an exchange; selecting mechanism at the exchange for BXtBDdlD the line thereat; a circuit supplied in addition to the line circuitfor governing the operation of the selecting mechanism; switching mechanism at the telephone stations for operating the selecting mechanism over its governing circuit; electro-magnctic mechanism at the stations in bridge of the telephone line serving when deenergized to prevent the operation of the switching mechanism at the telephone stations and when energized to permit the operation of said switching mechanism, there being present switching devices at the telephone stations for establishing circuit through the electro-magnetic mechanism at I 1,056,425

thereat; and means governed by the telephone station switching mechanism serving to operate the selecting mechanism for rendering inetTective the circuit. of the electromagnetic mechanism at a companion tele phone station.

(i. A telephone exchange system including a line connecting a plurality of telephone stations with an exchange; selecting mechanism at the exchange torexteutling the line thereat; a circuit supplied in addition to the line circuit for governing the operation of the selecting mechanism; switching mechanism at thetelephone stations for operating the selecting mechanism over its governing circuit; electromagnetic mechanism at the stations in bridge of the telephone line serving when decnergized to prevent the inciu sion of the telephone thereat in circuit with the line and when energized to pern'iit the inclusion of the telephones thercat in circuitwitl the line, there being present switching devices at the telephone stations for estah lisliing circuit through the clectro-magnetie mechanism thereat; and means governed by the telephone station switching mechanism serving to operate the selecting mechanism for rendering ineffective the circuit for electro-magnetic mechanism at a companion telephone station.

In witness whereof, I hereunto subscribe my name this fourth day of May A. 1)., 1911.

MORTON L. JOHNSON.

lVit-nesses MARGARET D. Rona, G. L. CRAGG.

Goptes of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, D. C. 

